The importance of automatic identification systems increases.
In particular contactless identification systems like transponder systems (for instance using an RFID tag) are suitable for a wireless transmission of data in a fast manner and without cable connections that may be disturbing. Such systems use the emission and absorption of electromagnetic waves, particularly in the high frequency domain.
RFID tags may be protected using a password which is stored unchangeable in a memory of the RFID tag. When a reader/writer desires access to the RFID tag for writing/reading, the reader/writer must send the password to the RFID tag to authenticate itself. However, such a system may be prone to failure, since it does not provide sufficient protection against systems trying to overcome the security barrier of the fixed password on a trial and error strategy.